Method and apparatus for forming, filing and sealing tubular packaging

ABSTRACT

A method and apparatus for forming a tubular package is disclosed. A longitudinally advancing strip of film material is guided about a mandrel so as to form a tubular body. As the film advances, margins of the film at the longitudinal edges are guided together into a fin and the fin is guided against the tubular body portion. The edge margins are then welded to each other and to the tubular body portion to form a tube closed cylinder. Individual packages may be formed and filled using conventional form, fill and sealing equipment.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to form, fill and seal packaging and in particular to an improved method and apparatus for forming tubular packaging of laminated film material.

[0002] Small tubular packages are commonly used for packaging small quantities of powders, granules and liquids. Such packaging is often used for providing samples sizes of cosmetics and other products, as primary packaging for single servings of sugar, coffee lightener and other food products and by suppliers to hotels for complementary, single portion sizes of shampoo, conditioner and the like. Such packaging is commonly formed of a strip of plastic film that is rolled into a tube having a longitudinal seam and end seals. The longitudinal seam may be formed by lapping one longitudinal edge over the other or by bringing the edges together as a fin. Where a lap seam is used, an edge of the film is exposed to the package contents. This usually does not pose a problem where dry products are to be packaged but may present a serious problem where liquids or cremes are to be contained in the package. This is particularly so if the packaging material is a laminated foil film since the liquid may cause the film to delaminate or the liquid may react with an interior, metallic foil layer of the laminate. With a fin seal, only the interior surface of the film material is exposed to the package contents. Accordingly, lap seam tubes are generally avoided for packaging liquids and cremes in favor of fin seam tubes. However, with a fin seal tube, the fin seal is generally free of the body of the package except, sometimes, at the ends of the tube where it is sealed to the tube body by welds forming the package ends. As a result, fin seam tubes are generally not as aesthetically pleasing as lap seam tubes.

SUMMARY OF THE INVENTION

[0003] In view of the above, it is a principal object of the present invention to provide an improved method of manufacturing fin seal tubes at a form, fill and seal machine wherein the resultant tube has its fin seal welded to the package body along the entire length of the tube.

[0004] A further object is to provide such a method and an apparatus for practicing the same that can operate to form packages from conventional film material at acceptable machine speeds.

[0005] A still further object is to provide such an apparatus that can readily be retrofitted into existing filling equipment.

[0006] The above and other objects and advantages are attained in accordance with the present invention by providing a method and apparatus for forming a tubular package by longitudinally advancing a strip of film material about a mandrel so as to form a tubular body of the advancing film material. As the film advances, margins of the film at the longitudinal edges are guided together into a fin and the fin is guided against the tubular body portion. The edge margins are then welded to each other and to the tubular body portion to form a tube. A package is the formed and filled from the tube using conventional techniques. Thus, the package may be formed and filled on a vertical form, fill and seal machine by making a first transverse seal across the tube whereafter product is introduced into the tube, after which a second transverse seal is made, capturing the product between the transverse seals. The filled tube is then severed from the tubular body portion. The severing occurs through the second transverse seal with the portion of that seal that remains attached to the tubular body forming the first transverse seal for the next tube to be formed. Alternatively, the packages may be formed on a rotary filler by advancing the tubular body into a holding jaw where a tube section is severed. The jaw is then advanced horizontally in an indexed dial plate to a sealing station where a first transverse seal is formed across one end of the tube section. The jaw is then again advanced horizontally to a filling station where product is introduced into the tube. The jaw in then again advanced to a second sealing station where a second transverse seal is made at the opposite end of the tube section. Next the dial plate advances the jaw to a die cutting trim station where both transverse seals are trimmed and shaped. Finally the dial plate advances the jaw to a knock out station where the finished tubes are knocked out of the holding jaw onto a conveyor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0007]FIG. 1 is a perspective view of tubular package such as may be formed in accordance with the present invention;

[0008]FIG. 2 is a sectional view taken along reference lines 2-2 of FIG. 1 in the indicated direction;

[0009]FIG. 3 is an enlarged fragmentary view of the longitudinal seal portion of the package;

[0010]FIG. 4 is a simplified view of a form, fill and seal machine for producing the package of FIG. 1;

[0011]FIG. 5 is a sectional view taken along reference lines 5-5 of FIG. 4 in the indicated direction; and,

[0012]FIG. 6 is a detail view of the folding of the film as it advances through the film guide and along the mandrel.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0013] Reference is now made to the drawings and to FIGS. 1-3 in particular wherein a package 10 is depicted comprising a body 12 along which a longitudinal seam 14 runs and ends 16 and 18. The body 12 is shown as being cylindrical but often the cylindrical tube is flattened to facilitate packing. The ends 16 and 18 are defined by seals or welds that extend transversely across the tube. The top end 18 may be flat, as shown, or may be die cut above the seal into funnel shape as is commonly done. Referring to FIG. 3, it will be noted that the longitudinal seam 14 is formed by the longitudinal edge margins 20,22 of the tube body being brought together into a fin 24 that is then folded over and against the body 12.

[0014] Referring now to FIG. 4, the package 10 is formed by advancing a strip of film 26 longitudinally from a supply roll 26 to mandrel 28. The film 26 may comprise any desired heat sealable plastic film material but preferably is a foil laminate wherein the foil is sandwiched between plastic layers. For example the inside (product facing) layer of the laminate may comprise a polyester film and the outside layer may comprise polyethylene. Both of these plastics are readily weldable using, for example heated sealing bars. If required by the film material, other welding techniques may be employed, such as r.f welding, which would be used for SARAN.

[0015] The film 26 is advanced by rollers 32 and 38 through a twist guide 30 to a fold guide 34 which serve to advance the initially flat film that is fed off supply roll 26 and guide and gradually twist the advancing film to form a cylindrical tubular body of the desired diameter about mandrel 28. The fold guide 34 further brings the longitudinal edge margins 20, 22 of the film material together to form a fin and then guides the fin to fold over the tubular body as shown in FIG. 6. A seam welder 36 at the mandrel welds the edge margins 20, 22 together to form a sealed fin and simultaneously welds the sealed fin to the tubular body portion at the mandrel. Finally, the tubular body portion must be delivered to the form, fill and sealing equipment.

[0016] If in-line vertical, form, fill and seal equipment are to be used, a transverse seal is formed in the tubular body below the mandrel by sealing bars 38 and product is introduced into the tube (whose bottom is now sealed) through the mandrel. After the filling process is completed a second transverse seam is formed across the tubular body sealing the now filled tube. The sealing bars further serves to cut the filled tube through the transverse seal, thereby providing the first seal for the next tube and the process is repeated. If desired the tube may be flattened before the transverse seams are formed to form a generally flat rather than a tubular package.

[0017] As noted above, the tubular body may also be used with rotary filling equipment (not shown) in which case the tubular body is fed into a holding jaw where a tube section is severed. The jaw is then advanced horizontally in an indexed dial plate to a sealing station where a first transverse seal is formed across one end of the tube section. The jaw is then again advanced horizontally to a filling station where product is introduced into the tube. The jaw in then again advanced to a second sealing station where a second transverse seal is made at the opposite end of the tube section. Next the dial plate advances the jaw to a die cutting trim station where both transverse seals are trimmed and shaped. Finally the dial plate advances the jaw to a knock out station where the finished tubes are knocked out of the holding jaw onto a conveyor.

[0018] Thus, in accordance with the above, the aforementioned objectives are effectively attained. 

Having thus described the invention, what is claimed is:
 1. A method for forming a package at a form, fill and seal machine, said method comprising the steps of: longitudinally advancing a strip of film material about a mandrel so as to form a tubular body, said strip of film material having opposed longitudinal edges; guiding marginal portions of said strip adjacent said longitudinal edges together so as to form a fin; guiding said fin against said tubular body as said strip advances toward said mandrel; and sealing said marginal portions to each other and said fin to said tubular body.
 2. The method in accordance with claim 1 wherein said marginal portions are simultaneously sealed to each other and to said tubular body.
 3. The method in accordance with claim 1 comprising the further steps of forming a first transverse seal across a section of said tubular body, filling a product into said tubular body section and then forming a second transverse seal across said tubular body.
 4. The method in accordance with claim 1 wherein said marginal portions are sealed to each other and said fin is sealed to said tubular body by welding the same.
 5. An apparatus for forming a package comprising: a mandrel; a film material supply, means for longitudinally advancing a strip of film material from said supply and about said mandrel; means for guiding said advancing strip into a tubular body; means for guiding longitudinal edge margins of said strip together to form a fin as said strip advances toward said mandrel; means for guiding said fin to fold against said tubular body; means for sealing said longitudinal edge margins to each other; and means for sealing said fin to said tubular body.
 6. The apparatus of claim 5 wherein a single welder seals said longitudinal edge margins and seals said fin to said tubular body. 